A standard easy-open package comprises a vessel having a flat rim and a cover foil that is bonded to the vessel at the rim. The vessel and foil together form one or more compartments that can contain respective foodstuffs, although it is within the scope of this invention for the package to contain other materials. Typically the vessel has upwardly projecting ribs that define the individual compartments and the foil is bonded to these ribs too. Both the vessel and the foil can be made of a metal, of a synthetic-resin, or of a laminate of both. A particularly advantageous system has a rigid plastic vessel to which is bonded a plastic-coated metallic foil, the bonding being done ultrasonically along bond lines running around the perimeters of the compartments. It is also of course possible to form the perimeter bond in a cold process, with an adhesive, or otherwise.
In order to remove the foil it is standard to provide it at one edge of the package with an outwardly projecting flap or tab that can be gripped by the user and pulled up away from the vessel. Such a system has the disadvantage that the manufacturer of the product must trade off a strong bond necessary to form a good hermetic seal that protects the contents and that stands up to shipping stresses against a weak bond that makes it possible to tear off the foil without using excessive force or destroying the entire package. Furthermore the outwardly projecting tearoff tab poses an inconvenience to boxing and handling the package, and often is damaged or otherwise rendered useless.
It is also known to form the cover foil with a tear line, that is a weakened strip typically formed by perforating the foil or reducing its thickness along the line, that runs around the compartment. In this case the user grips a portion of the tear-out portion that is bounded by this tear line and pulls it off the package. The problem with this system is that the foil is often poked down into the contents of the package as it is removed, making such removal messy and unsanitary. This problem can be partially solved by applying a second grip tab that is secured to the tearout section so it can be pulled up, but this extra element increases production costs too much for a throwaway item.